Hose assemblies used to carry fuels are well known in the art. The hose should preferably be strong and resistant to heat and chemical degradation. These hoses are subject to chemical breakdown by the various fluids which flow through them. Further, these hoses are typically routed through the engine compartment of the vehicle to deliver fuel to the engines. These engines are hot and thus, the hoses used to carry fuel are subject to breakdown from the heat.
TEFLON hoses provide the necessary physical properties for carrying fuels. A problem with these types of hoses is that when used alone, i.e., only TEFLON, they tend to get bent during installation and they kink. This kink remains permanent and provides resistance to fluid flow through the hose. To solve this problem, one known hose assembly includes an inner TEFLON tubular member. The inner tubular member is surrounded by a tightly wound metallic braid. The metallic braid allows the teflon inner tubular member to bend to a certain degree without kinking. However, if bent past a certain point the metallic braid aids in the kinking of the inner tubular member. This assembly, however, has three major disadvantages. First, the metallic braid tends to abrade the exterior of the inner tubular member. This causes leaks from the inner tubular member. The second problem is that the exterior metallic braided casing is thermally and electrically conductive. More important is that the metallic braid will retain heat and transfer the heat to the fuel moving through the inner tubular member causing fuel system problems. Finally, if used in an automotive environment, the metallic braid transmits noise during operation of the vehicle which is undesirable.
Schuerer U.S. Pat. No. 3,547,162 issued Dec. 15, 1970 discloses a plastic pipe assembly. The assembly includes an inner liner of a synthetic plastic made from cross linked olefinic polymers. A fiber braided layer is disposed over the inner liner. Finally, a foamed layer of synthetic plastic is disposed about the synthetic fiber reinforcement. By utilizing cross linked olefinic polymers, the system is deficient in that it cannot be used to carry vehicle fuels, as such fuels would degrade the inner liner.
The Yap et al U.S. Pat. No. 4,249,971 discloses an elastomeric hose having an elastomeric inner liner 12. A reinforcing or braided layer 14 is disposed about the inner liner 12. An elastomeric foam outer layer or jacket 16 is disposed about the intermediate reinforcing layer 14.